PubMed Health⌕ Search

Biomedical subjects

M M Perry

Publications and source records attributed to M M Perry.

At least 19 recordsLinked to original sources
PubMed1998

Chronology of events in the first cell cycle of the polyspermic egg of the domestic fowl (Gallus domesticus).

The nuclear population in the polyspermic egg of the domestic hen was examined in whole-mount preparations of the germinal disc. The numbers of nuclei varied in groups of hens from averages of 5.9 to 26, depending on days from insemination. Changes in development from initial formation of pronuclei to the early mitoses of the zygote nucleus were staged according to the position of the egg in the oviduct. The findings substantiated earlier accounts on the timing of the apposition of the parental pronuclei towards the end of the first cell cycle. Additionally, analysis of the spatial distribution of accessory spermatozoal nuclei showed a slight, but significant, dispersal from a clustered arrangement at this time.

Animals↗
PubMed1993

Transgenesis in chickens.

The application of transgenic technology to domestic poultry offers an alternative means to conventional practice for improvement of this highly productive agricultural species. The hen's reproductive system has unique characteristics which have imposed limitations on the use of established methods for artificial gene transfer. In this article, we review the various strategies that have been adopted to overcome the problem. Target sites for gene insertion include the fertilized ovum, the blastodermal embryo in the unincubated egg, and the primordial germ cells. Notable success in obtaining somatic and germline transformation has been achieved with the use of retroviral vectors to infect the blastodermal embryo. Current attempts to introduce DNA directly into the genome, without resort to pathogen-derived vectors, are discussed.

Animals↗
PubMed1991

Embryonic expression of beta-actin-lacZ hybrid gene injected into the fertilized ovum of the domestic fowl.

An experiment was carried out to investigate the expression of cloned DNA injected into the germinal disc of the chick fertilized ovum. The beta-actin-lacZ hybrid gene, MiwZ, was injected, in the closed circular form, into the cytoplasm of the germinal disc at the single-cell stage. The embryos were cultured in vitro, then in recipient eggshells up to day 4 of incubation. The survival rate of the embryos at day 4 was 42% (55/130), and the rate of embryos expressing MiwZ was 64% (35/55). Twenty-two embryos expressed the MiwZ in both embryonic and extraembryonic tissues, while the remainder expressed the MiwZ in only extraembryonic tissues. Mosaic expression was observed in most of the embryos expressing MiwZ in embryonic tissues. Expression throughout all tissues of the embryo including blood cells occurred in one case. In this case, the injected DNA was assumed to have integrated at an earlier stage. The results indicate that it is now possible to investigate the promoter activities of introduced exogenous genes as well as the effect of introduced genes on embryogenesis in early chick embryos. This technique may also facilitate the production of transgenic chicks.

Actins↗
PubMed1989

Episomal replication of cloned DNA injected into the fertilised ovum of the hen, Gallus domesticus.

We describe preliminary experiments to analyse the fate of cloned DNA microinjected into the cytoplasm of the chick fertilised ovum. The reporter gene construct pRSVcat was injected into the germinal disc before the first cleavage division, and the chick embryos were cultured for up to 7 days using the method of Perry (Nature 331:70-72, 1988). Linear plasmid molecules ligated rapidly after injection to form high-molecular-weight DNA molecules consisting mainly of random concatemers of the injected plasmid. Recombination involving circular molecules resulted in head-to-tail multimers of the plasmid. Some of the DNA was lost after injection, but the remainder was replicated approximately 20-fold during the first 24 h of development. Between days 1 and 7 in culture, the DNA was gradually lost and diluted out as the embryos developed. By day 7 in culture plasmid DNA was detectable in only 30% of the cultures analysed. No evidence for chromosomal integration of the exogenous DNA was obtained, suggesting that the plasmid DNA persisted episomally. Expression of the reporter gene construct pRSVcat was detected in day 2 and day 7 embryos.

Animals↗
PubMed1989

Development in culture of the chick embryo from cleavage to hatch.

1. Early uterine embryos were obtained from hens by induced oviposition 7.5-8.0 h after the preceding egg was laid. They were cultured in vitro and then in recipient shells to hatch. As controls, embryos from freshly laid eggs were cultured in recipient shells to hatch. 2. For embryos cultured from uterine eggs, the hatch rate was 22.5%, and for embryos cultured from laid eggs, the hatch rate was 62.5%. 3. The weight of the chicks hatched from culture was about 60% of the weight of the preceding egg, or donor egg. Male and female chicks reached maturity and have produced viable offsprings. 4. The results show that it is possible to grow chick embryos in culture from the early cleavage stage (stage II) to hatch. They extend earlier findings on the culture of embryos from the blastoderm stage (Stage X) to hatch. The technique provides a basis for investigations on chick embryo cryopreservation.

Animals↗
PubMed1988

A complete culture system for the chick embryo.

The embryonic lifespan of the chick is 22 days. Development in the first day takes place in the oviduct, and in the remaining 21 days in the shelled egg. There have been few attempts to culture oviductal embryos, though methods covering the first few days of development in ovo are well established and a method for the final 18 days of development through hatching has recently been devised. I have now succeeded in culturing the fertilized ovum of the chick (Gallus domesticus) for the total embryonic period by growing it in a series of separate culture systems. This is the first report of a complete in vitro method for a homoiothermic animal. The technique opens the way to the investigation of developmental events in birds that require access to the embryo at the single-cell stage, and in particular to the genetic manipulation of the fertilized ovum.

Animals↗
PubMed1987

Occurrence of waxy-textured yolk in the egg of the domestic hen (Gallus domesticus).

An unusual yolk material (waxy yolk) was identified in some hard boiled yolks of one strain of domestic hen. Its structure was consistent with it being formed from normal yolk through disruption of the yolk spheres. These are normally stable during even long periods of storage. Formation occurs mainly after ovulation, during passage of the egg down the oviduct; only rarely could it be found in the larger follicles of the ovarian hierarchy. In the flock of birds examined the incidence of eggs with waxy yolk was 75% of all eggs laid over a 7 d period. Of the 173 birds tested, the eggs of only 17 birds were totally unaffected; all eggs of 82 birds contained this material. The results of a hatchability trial indicated this material had no apparent influence on the embryo or hatchability.

Animals↗
PubMed1987

Nuclear events from fertilisation to the early cleavage stages in the domestic fowl (Gallus domesticus)

The changes in nuclear morphology from fertilisation to the 16-blastomere stage of development in the domestic fowl were examined in sections of the germinal disc stained with DAPI (4',6'-diamidino-2-phenylindole) or with the Feulgen technique. By one hour after the estimated time of ovulation, the second meiotic division of the ovum was completed and the spermatozoal heads (3-9) in the germinal disc had transformed into pronuclei. During the following two hours all the pronuclei enlarged, and two of them became juxtaposed. Mitotic figures and large pronuclei were observed at 4 hours. The zygote nucleus went through 3-4 division cycles in synchrony. The supernumerary male nuclei divided once, at most, and all showed evidence of degeneration by the 4-blastomere stage, at about five hours. Therefore, the nuclei destined to form the future chick embryo follow a pattern of behaviour during fertilisation and early cleavage similar to that of animals in general.

Animals↗
PubMed1985

Exclusion of plasma lipoproteins of intestinal origin from avian egg yolk because of their size.

Increasing the fat content of the diet increases the proportion of large triglyceride-rich (TGR) lipoproteins (portomicrons) in laying-hen plasma, but has no effect on the size distribution of yolk TGR-lipoproteins. Electromicrographs of the ovarian follicle walls of hens fed a high-fat diet show the presence of numerous portomicron-like particles in the lumen of the thecal capillaries, in the pericapillary spaces and in the theca interna, but portomicrons were absent from the basal lamina, between the granulosa cells and in newly deposited yolk. Most of the lipoprotein lipase activity in the ovarian follicles is associated with the granulosa cells, but total activity in the follicle is very small compared to heart or adipose tissue. The results indicate that the ovarian follicle of the laying-hen specifically excludes lipoproteins of intestinal origin from yolk, most probably because they are too large to pass through the connective tissue matrix of the basal lamina. The low lipoprotein lipase activity of the ovarian follicle, together with its distribution within the follicle wall, indicates that the ovarian follicles make little contribution to catabolism of circulating portomicrons.

Adipose Tissue↗
PubMed1985

Follicular growth and atresia in the ovaries of hens (Gallus domesticus) with diminished egg production rates.

Diets containing 3.5, 1.0 and 0.1% calcium were fed from the age of 42 weeks to individually caged laying hens. Ovaries were examined at 46-49 and 70 weeks of age for changes in the follicular population corresponding to the lowered egg production rates of birds given calcium-deficient diets (1.0% and 0.1%) and older birds given a normal diet (3.5%). Growth rates of follicles from 3.5 mm diameter to ovulation were not changed by the level of dietary calcium in 46-49-week-old birds. The number of atretic small follicles (less than or equal to 8 mm diam.) increased in old and calcium-deprived birds, resulting in lower numbers of viable follicles in the intermediate stages of growth (3-8 mm diam.). There was also an increase in the number of small follicles (1-2 mm diam.) starting to grow in 70-week-old birds which may have partly compensated for the increased loss by atresia. Birds of all ages on all diets were able to produce large follicles up to ovulable size. The main feature of poor laying birds was a reduction in the ovulation rate due to the loss of large follicles (greater than 8 mm diam.) by atresia, an event seen rarely in the birds with good laying performance. As atresia is the normal fate of most of the small follicles, the mechanisms controlling atresia in the small follicles and the large follicles appear to be independent.

Animals↗
PubMed1984

The binding of very low density and low density lipoproteins to the plasma membrane of the hen's oocyte. A morphological study.

The binding of lipoproteins to the oocyte plasma membrane of the domestic fowl (Gallus domesticus) was examined by electron microscopy in preparations of the ovarian follicle in the main phase of yolk formation. Numerous particles, 26 nm in diameter, were present on the untreated membrane. They were dissociated from the membrane by incubation at 4 degrees C in buffer at pH 6.2 and with heparin at pH 7.4. Added calcium was not required for binding, though the number of bound particles was reduced by treatment with EDTA. Very low density (VLD) lipoproteins from laying hen's plasma were found to bind to the denuded membrane and to correspond in size to the native particles. The results suggest that the binding characteristics are similar in quality to those determined for the binding of low density (LD) lipoproteins to mammalian cells. The oocytes, however, bound 100-fold more particles per unit length of membrane. VLD and LD lipoproteins from immature hens also adhered to the denuded membrane, although their apoprotein composition was very different from that of laying hen VLD lipoproteins. LD lipoproteins from immature hens and VLD lipoproteins from laying hens both contained apo-B, which formed about 80 and 35%, respectively, of the total apolipoproteins. Apo-VLDL-II is the other major apoprotein identified in laying-hen VLD lipoproteins. Apo-VLDL-II was not positively identified as a component of immature-hen LD lipoproteins and could only have been present as a minor component.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Role of atresia in establishing the follicular hierarchy in the ovary of the domestic hen (Gallus domesticus).

At peak laying periods the ovary of the domestic hen contained 30-100 small yolky follicles with diameters varying between 1 and 8 mm. In general, the number of these healthy follicles decreased with increasing size in that there were about 20 follicles with a diameter of 1-2 mm and 1 follicle (mean less than 1) with a diameter of 7-8 mm. The number of follicles with diameters greater than 8 mm (the hierarchy of large, yolky follicles) varied between 4 and 7. By using a dye-marker, growth from 3 to 5 mm was estimated to take 3 days, from 5 to 8 mm, 2 days and from 8 mm to ovulation, 6 days. No information was obtained for growth between 1 and 3 mm because the dye did not enter these smaller follicles. Between 5 and 25 small yolky follicles were atretic. The reduction in the number of follicles with time and the high incidence of atresia suggests that this is a normal fate of small yolky follicles in birds with a high rate of lay. In marked contrast, only one large yolky follicle was observed to be atretic throughout the whole experiment. These two very different levels of atresia serve to define two distinct groups of follicles in the size range studied. Ovulation rate appears to be the product of two complementary mechanisms, one for the initiation of growth and the other controlling the rate at which the small yolky follicles are lost through atresia.

Animals↗
PubMed1980

Incorporation of 3H-oleic acid by the proximal convoluted tubule cells of the chick (Gallus domesticus). Electron microscopic autoradiographic study.

Lipid metabolism in the cells of the renal proximal convoluted tubules (PCT) was investigated in healthy fowls and in fowls with the Fatty Liver and Kidney Syndrome (FLKS). The tissue was fixed at 10-25 min intervals after intravenous injection of 3H-oleic acid. The distribution of autoradiographic grains was analysed by the "circle method". In normal cells most of the silver grains were associated with the cytoplasmic organelles. Lipid droplets and Golgi elements had the highest specific activity relative to the nuclear activity, which was little above background level. Lysosome-like bodies and mitochondria had lower values. In the cells of the FLKS-affected birds a large porportion of the grains was located over the lipid droplets, which are abundant in this condition. The specific activity of the cytoplasmic organelles was barely 2-fold higher than the nuclear activity. The results suggest that there is a diminished incorporation of esterified fatty acids by the organelles of these cells and that the excess is transferred to the lipid droplets. The identity of low electron density particles observed in the PCT cell of severely affected birds is discussed.

Animals↗
PubMed1980

Cellular changes in the granulosa layer of the maturing ovarian follicle of the domestic fowl.

1. The relationships between length, width and height of the maturing ovarian follicle of the domestic fowl (Gallus domesticus) are shown. 2. During the rapid-growth phase (yolk deposition) of the oocyte, i.e. an increase in size from about 9 mm diameter to 35 mm diameter, there is about a 15-fold increase in its surface area. During this time the number of granulosa cells adjacent to the oocyte increases by about 5-fold. 3. The granulosa cells become flatter during the growth period of the follicle, consequently increasing their surface area adjacent to the oocyte by about 3-fold. 4. Together the change in shape of the granulosa cells and the increase in their number account for the increase in area of the granulosa layer during follicular growth. 5. Measurement of the DNA content of the granulosa layer indicated a progressive decrease in the cellular content of DNA as the follicle matures.

Animals↗